State Highway 35 between Ōpōtiki and Gisborne is now officially closed after crumbling into a river due to the extreme weather.
SH35 at Motu River collapsed along the centre line this evening with the eastbound lane falling into the river.
Traffic had been reduced to a single lane due to the large crack in the road since Monday.
At a press conference today, Minister for Emergency Management Kieran McAnulty said there was a "high likelihood" that the highway would have to be closed.
McAnulty said funding was pre-emptively approved to send resources to communities that would be isolated due to this closure.
The detour for vehicles (except over-dimension vehicles) is SH2 through Waioeka Gorge, but Waka Kotahi advises caution. Traffic is reduced to a single lane due to the underslip 7km west of Matawai.
The state highways throughout New Zealand have been hit hard by the recent severe weather with slips, dropouts and flooding in a number of locations.
Lake Ōhau village is cut off by severe flooding in the area after a bridge on Lake Ōhau Rd was swept away on Tuesday so motorists could not cross.
McAnulty said although communities are isolated, they have supplies and power. It is just an access issue.
"They are okay and liaising with local Civil Defence outfits," McAnulty said.
"We have spoken to all mayors of the affected communities and they are happy with the support they are receiving."